ScienceDaily (Jan. 26, 2012) — NASA's Kepler mission has discovered 11 new planetary systems hosting 26 confirmed planets. These discoveries nearly double the number of verified Kepler planets and triple the number of stars known to have more than one planet that transits

...yep. And unless they were MUCH rockier than our KBOs are thought to be, they wouldn't last very long in terms of geological time...they'd become garden-variety asteroids in short order.

Let's not go off the deep end on the speculation front, please. Hot Jupiters, Neptunes, super-Earths, etc. are acceptable discussion topics since there is considerable observational evidence that they exist. I'm sure as time marches on exo-solar system research will provide even more surprises for us to discuss.

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A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.

It's worth noting (a point I trimmed from the article) that the bin for earth-sized planets with periods of 64 to 128 days has zero observed candidates although in the 407 days of observations, any such world must have transited between three and seven times while Kepler was watching (discounting the possible lapses of downtime), and so we aren't actually waiting, as the mission goes on, to see any new transits there: As the mission goes on, any such planet will only repeat what it's already done (e.g., transit, and be missed in the noise, or not transit... or not exist).

That's a bin two slots to the left (two powers of two shorter) than the Earth itself, and Kepler found none. The prospects for the Earth's actual bin are distinctly poorer. Kepler did, however, find five candidates in the bin corresponding to periods of 64 to 128 days and sizes one notch larger than Earth: worlds with radii 1.2 to 1.4 Re. That corresponds to a 2% abundance of such worlds, and every trend indicating continued drop-off with smaller sizes and greater distance.

re: Brellis's question, the probability of a randomly-placed observer being situated for the geometry to allow them to witness the Earth transiting the Sun is 0.29%. For a world twice as far out, the probability is half that. For a world twice as close, the probability is double that. In our solar system, the easiest worlds for Kepler to detect would be, in descending order: Venus, Earth, Jupiter, Saturn. As of this release, an exact Venus analogue *could* have been detected, but wasn't.

Kepler could detect exact analogues of almost any of the planets in the solar system, given the right luck and an un-noisy enough star. At levels of noise in the present analyses, it now seems quite unlikely that the abundance of terrestrial worlds in the habitable zone will be high enough for us to get good statistics on the frequency function out that far. We could always luck into a single detection, but getting statistical significance seems very unlikely. This highlights the importance either of ways to find repeated transits buried deep in the noise or follow-up missions that monitor a yet-larger number of stars.

John, I was unsure in the article what you did to de-bias the frequency (or is that a reference to a pre-processed value provided by the Kepler team?). Are you modifying each frequency bin by the chance to detect an earth-like planet at that bin?

Edit: I also repeat the question left on the article - Are these sun-like stars, or is there a bias in this dataset to stars of a different size than the sun? Many more small stars in the galaxy, larger stars are easier to see at a distance. Really needs a 3-d representation with star's mass or radius as another axis, and possibly a 4D representation with the star's metallicity or distance from Earth.

Edit^2: Nevermind, I see where you responded that the data is all stars lumped together, and that there isn't enough data to separate the stars into separate bins.

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Space Enthusiast Richard Hendricks --"The engineers, as usual, made a tremendous fuss. Again as usual, they did the job in half the time they had dismissed as being absolutely impossible." --Rescue Party, Arthur C ClarkeMother Nature is the final inspector of all quality.

Great to see you posting again JRehling. Here's what I take from the Kepler release.1/ 0.7% is plenty. I reckon that means about 100 within 100LY2/ The estimate is premature. Let's wait for the full data set and the long analysis.3/ I've heard it stated (in the infamous IAU debate on the definition of "planet") that the solar system is dynamically 'full' in the sense that the planets are packed together as closely as possible apart from the gap where the asteroid belt is located. The dense compact systems Kepler has found seem to contradict this hypothesis, unless in fact they are young systems that will in due course eject or swallow most of the objects now observed. 4/ I love all these planets and their extreme diversity, no doubt arising from peculiar histories yet to be elucidated. (Just look at the Iapetus 'fairy tale' for an example of reality exceeding imagination.)

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